summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/bcm47xx_wdt.c
blob: 5c7011cda6a6a65e1510022c06a8de3b4420a96b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
/*
 *  Watchdog driver for Broadcom BCM47XX
 *
 *  Copyright (C) 2008 Aleksandar Radovanovic <biblbroks@sezampro.rs>
 *  Copyright (C) 2009 Matthieu CASTET <castet.matthieu@free.fr>
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/reboot.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/watchdog.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/ssb/ssb_embedded.h>
#include <asm/mach-bcm47xx/bcm47xx.h>

#define DRV_NAME		"bcm47xx_wdt"

#define WDT_DEFAULT_TIME	30	/* seconds */
#define WDT_MAX_TIME		255	/* seconds */

static int wdt_time = WDT_DEFAULT_TIME;
static int nowayout = WATCHDOG_NOWAYOUT;

module_param(wdt_time, int, 0);
MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
				__MODULE_STRING(WDT_DEFAULT_TIME) ")");

#ifdef CONFIG_WATCHDOG_NOWAYOUT
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout,
		"Watchdog cannot be stopped once started (default="
				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
#endif

static unsigned long bcm47xx_wdt_busy;
static char expect_release;
static struct timer_list wdt_timer;
static atomic_t ticks;

static inline void bcm47xx_wdt_hw_start(void)
{
	/* this is 2,5s on 100Mhz clock  and 2s on 133 Mhz */
	ssb_watchdog_timer_set(&ssb_bcm47xx, 0xfffffff);
}

static inline int bcm47xx_wdt_hw_stop(void)
{
	return ssb_watchdog_timer_set(&ssb_bcm47xx, 0);
}

static void bcm47xx_timer_tick(unsigned long unused)
{
	if (!atomic_dec_and_test(&ticks)) {
		bcm47xx_wdt_hw_start();
		mod_timer(&wdt_timer, jiffies + HZ);
	} else {
		printk(KERN_CRIT DRV_NAME "Watchdog will fire soon!!!\n");
	}
}

static inline void bcm47xx_wdt_pet(void)
{
	atomic_set(&ticks, wdt_time);
}

static void bcm47xx_wdt_start(void)
{
	bcm47xx_wdt_pet();
	bcm47xx_timer_tick(0);
}

static void bcm47xx_wdt_pause(void)
{
	del_timer_sync(&wdt_timer);
	bcm47xx_wdt_hw_stop();
}

static void bcm47xx_wdt_stop(void)
{
	bcm47xx_wdt_pause();
}

static int bcm47xx_wdt_settimeout(int new_time)
{
	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
		return -EINVAL;

	wdt_time = new_time;
	return 0;
}

static int bcm47xx_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &bcm47xx_wdt_busy))
		return -EBUSY;

	bcm47xx_wdt_start();
	return nonseekable_open(inode, file);
}

static int bcm47xx_wdt_release(struct inode *inode, struct file *file)
{
	if (expect_release == 42) {
		bcm47xx_wdt_stop();
	} else {
		printk(KERN_CRIT DRV_NAME
			": Unexpected close, not stopping watchdog!\n");
		bcm47xx_wdt_start();
	}

	clear_bit(0, &bcm47xx_wdt_busy);
	expect_release = 0;
	return 0;
}

static ssize_t bcm47xx_wdt_write(struct file *file, const char __user *data,
				size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			expect_release = 0;

			for (i = 0; i != len; i++) {
				char c;
				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					expect_release = 42;
			}
		}
		bcm47xx_wdt_pet();
	}
	return len;
}

static struct watchdog_info bcm47xx_wdt_info = {
	.identity 	= DRV_NAME,
	.options 	= WDIOF_SETTIMEOUT |
				WDIOF_KEEPALIVEPING |
				WDIOF_MAGICCLOSE,
};

static long bcm47xx_wdt_ioctl(struct file *file,
					unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_value, retval = -EINVAL;;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &bcm47xx_wdt_info,
				sizeof(bcm47xx_wdt_info)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);

	case WDIOC_SETOPTIONS:
		if (get_user(new_value, p))
			return -EFAULT;

		if (new_value & WDIOS_DISABLECARD) {
			bcm47xx_wdt_stop();
			retval = 0;
		}

		if (new_value & WDIOS_ENABLECARD) {
			bcm47xx_wdt_start();
			retval = 0;
		}

		return retval;

	case WDIOC_KEEPALIVE:
		bcm47xx_wdt_pet();
		return 0;

	case WDIOC_SETTIMEOUT:
		if (get_user(new_value, p))
			return -EFAULT;

		if (bcm47xx_wdt_settimeout(new_value))
			return -EINVAL;

		bcm47xx_wdt_pet();

	case WDIOC_GETTIMEOUT:
		return put_user(wdt_time, p);

	default:
		return -ENOTTY;
	}
}

static int bcm47xx_wdt_notify_sys(struct notifier_block *this,
	unsigned long code, void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
		bcm47xx_wdt_stop();
	return NOTIFY_DONE;
}

static const struct file_operations bcm47xx_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.unlocked_ioctl	= bcm47xx_wdt_ioctl,
	.open		= bcm47xx_wdt_open,
	.release	= bcm47xx_wdt_release,
	.write		= bcm47xx_wdt_write,
};

static struct miscdevice bcm47xx_wdt_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &bcm47xx_wdt_fops,
};

static struct notifier_block bcm47xx_wdt_notifier = {
	.notifier_call = bcm47xx_wdt_notify_sys,
};

static int __init bcm47xx_wdt_init(void)
{
	int ret;

	if (bcm47xx_wdt_hw_stop() < 0)
		return -ENODEV;

	setup_timer(&wdt_timer, bcm47xx_timer_tick, 0L);

	if (bcm47xx_wdt_settimeout(wdt_time)) {
		bcm47xx_wdt_settimeout(WDT_DEFAULT_TIME);
		printk(KERN_INFO DRV_NAME ": "
			"wdt_time value must be 0 < wdt_time < %d, using %d\n",
			(WDT_MAX_TIME + 1), wdt_time);
	}

	ret = register_reboot_notifier(&bcm47xx_wdt_notifier);
	if (ret)
		return ret;

	ret = misc_register(&bcm47xx_wdt_miscdev);
	if (ret) {
		unregister_reboot_notifier(&bcm47xx_wdt_notifier);
		return ret;
	}

	printk(KERN_INFO "BCM47xx Watchdog Timer enabled (%d seconds%s)\n",
				wdt_time, nowayout ? ", nowayout" : "");
	return 0;
}

static void __exit bcm47xx_wdt_exit(void)
{
	if (!nowayout)
		bcm47xx_wdt_stop();

	misc_deregister(&bcm47xx_wdt_miscdev);

	unregister_reboot_notifier(&bcm47xx_wdt_notifier);
}

module_init(bcm47xx_wdt_init);
module_exit(bcm47xx_wdt_exit);

MODULE_AUTHOR("Aleksandar Radovanovic");
MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
OpenPOWER on IntegriCloud